Comparison and generalisation of spatial patterns of the urban heat island based on normalized values

The studied medium-sized cities (Szeged and Debrecen, Hungary) are located on a low and flat plain. Data were collected by mobile measurements in grid networks under different weather conditions between April 2002 and March 2003 in the time of maximum development of the urban heat island (UHI). Tasks included: (i) interpretation and comparison of the average UHI intensity fields using absolute and normalized values; (ii) classification of individual temperature patterns into generalized types by cities using normalization and cross-correlation. According to our results, spatial distribution of the annual and seasonal mean UHI intensity fields in the studied period have concentric shape with some local irregularities. The UHI pattern classification reveals that several types of the structure can be distinguished in both cities. Shifts in the shape of patterns in comparison with the centralized pattern are in connection with the prevailing wind directions.